Binary Installers

Binary distributions of PostGIS are available for various operating systems.

Windows

More details about getting up and running with windows can be found on Windows Downloads page.

OSX

A popular distribution particularly for newbies is Postgres.app. It includes generally latest version of PostgreSQL, PostGIS, and PLV8.
Great for development and testing. Do not mix with other installations.

Homebrew users can just run “brew install postgis” and tends to be a favorite for more advanced users since there are brew scripts
for most of the popular PostgreSQL extensions, not always present in other Mac distributions.

BigSQL distribution includes versions for MacOSX.
It generally has latest version of PostGIS and ogrfdw.

OpenSUSE and SUSE

Distributions targeting more than one OS (these include PostgreSQL and many other PostgreSQL extensions)

BigSQL - Supports 64-bit for Linux (RedHat, Debian), MacOSX 64-bit, and Windows 64-bit.
It generally has latest version of PostGIS and ogrfdw for all OS supported. As such, it’s ideal if you have users on different OS and want a consistent set of PostGIS related features for all.
Refer to BigSQL: PostGIS Install and BigSQL: How to create a Spatial Database for PostGIS specific install instructions.

EnterpriseDb PostgreSQL - Supports 32-bit/64-bit Linux, MacOSX, Windows
Note that the MacOSX PostGIS package
and EDB Windows PostGIS package have different maintainers, so offerings are not equivalent.
Both versions generally have latest minor version of PostGIS, but versions of libraries used may be different,
other PostGIS related extensions like pgRouting, postgis_sfcgal are packaged with the windows but not OSX version.

Additional Install Guides

Getting Started

These instructions are for PostgreSQL 9.1 and higher, PostGIS 2.2 and higher that is compiled with raster support.
Note: if you have postgis, without raster support, you can not use CREATE EXTENSION. Refer to PostGIS install.

Enabling PostGIS

PostGIS is an optional extension that must be enabled in each database you want to use it in before you can use it. Installing the software is just the first step.
DO NOT INSTALL it in the database called postgres.

Connect to your database with psql or PgAdmin. Run the following SQL.
You need only install the features you want:

Upgrading PostGIS

To upgrade PostGIS, you first have to install the latest binaries and then upgrade each database you have PostGIS installed in

For example connect to database you want to upgrade and if you just installed binaries for 2.1.3
You can upgrade from 2.0 to 2.1, 2.2 et.c using this approach. To go from 1.* to 2.* you need to do a hard upgrade.
Refer to PostGIS install for more extensive instructions.
Note: that as of PostGIS 2.1.3 and PostGIS 2.0.6, you need to set environment variables to get full features.